This section provides background information related to the present disclosure which is not necessarily prior art.
Vehicles are known to incorporate HVAC systems to improve the comfort of the people within the passenger compartment of the vehicle. The HVAC systems heat and cool air blown through the HVAC system using a heating heat exchanger and/or a cooling heat exchanger. The heating heat exchanger typically utilizes the engine coolant as a source of heat for heating the air. The cooling heat exchanger is typically an evaporator which is part of an air conditioning system in the vehicle powered by the engine of the vehicle. The air blown through the HVAC system comes from air outside the vehicle, air inside the passenger compartment of the vehicle or a combination of the air outside the vehicle and the air inside the passenger compartment of the vehicle. The air being blown through the HVAC system is conditioned (heated/cooled) and is then directed into the passenger compartment of the vehicle through one or more outlet vents.
Although these vehicle HVAC systems have worked for their intended purposes, some disadvantages remain. For instance, the air distribution system within these HVAC systems is designed to provide a defrost mode where air is directed to the front windshield through a defrost outlet, a face mode where air is directed through vents in the instrument panel toward the upper portion of the body of the passengers and a floor mode where air is directed toward floor outlets that direct air towards the feet of the passengers. Typically, the defrost mode is used to defog the windshield, the face mode is used during cooling of the passenger compartment and the floor mode is used during heating of the passenger compartment.
Some HVAC systems allow for a combination of modes to be set by the passenger. These combination modes can be defrost/foot mode, face/foot mode or what is termed bi-level or any other combination of two or more modes. Other than these bi-level modes, the typical HVAC system directs all air to the vents in the instrument panel when the face mode is selected and all air to the floor vents when the floor mode is selected.
In some designs, it may be advantageous to always supply some of the conditioned air to the floor vents. Always supplying some air flow to the floor vents will ensure the circulation of air to the passenger's feet. For example, when the HVAC system is set to face mode during the cooling of the passenger compartment, it may be advantageous to supply a small amount of cool air flow to the floor vents to increase the comfort level for the passengers in the vehicle.